Influenza Vaccines
What You Need to Know

What are the risks from influenza vaccine?

Getting influenza is much riskier than getting the influenza vaccine. However, a vaccine, like any medicine, is capable of causing problems, such as severe allergic reactions. The risk of the influenza vaccine causing serious harm, or death, is extremely small.

Inactivated Influenza Vaccine:

Mild problems:

  • soreness, redness, or swelling where the shot was given
  • fever
  • aches

If these problems occur, they usually begin soon after the shot and last 1-2 days.

Severe problems:

  • Life-threatening allergic reactions are very rare. If they do occur, it is within a few minutes to a few hours after the shot.

Live, Intranasal Influenza Vaccine:

Mild problems:
Some children and adolescents 5-17 years of age have reported:

  • runny nose, nasal congestion or cough
  • fever
  • headache and muscle aches
  • abdominal pain or occasional vomiting or diarrhea

Some adults 18-49 years of age have reported:

  • runny nose or nasal congestion
  • sore throat
  • cough, chills, tiredness/weakness
  • headache

These symptoms did not last long and went away on their own. Even when they occur after vaccination, they may not have been caused by the vaccine.

Severe problems:

  • Life-threatening allergic reactions from vaccines are very rare. If they do occur, it would be within a few minutes to a few hours after the vaccination.
  • If rare reactions occur with any new product, they may not be identified until many thousands, or millions, of people have used the product. Like all vaccines, live, intranasal influenza vaccine is being monitored for unusual or severe problems.

Content derived from the Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases
and American Academy of Pediatrics Policy